1. Field of the Invention
The present invention relates to a wireless flash system which is used as an auxiliary illumination device of an image pickup apparatus etc. and capable of emission controlling a slave flash apparatus by wireless communication control from a commander flash apparatus (or a master flash apparatus).
2. Description of the Related Art
Conventionally known is a flash system which emission-controls a flash (slave flash) as auxiliary illumination for an image pickup apparatus by wireless using a commander flash of an image pickup apparatus under the optical communication control by a commander flash of the image pickup apparatus.
A flash system in a method for detecting on the slave flash apparatus side the data such as an amount of emission etc. as an emission time interval, and controlling a slave flash apparatus on the basis of the detection result has been disclosed (for example, Japanese Patent No. 3061437). Thus, the method of transmitting data in the emission time interval of a flash enables data of a larger number of bits to be transmitted at an emission frequency of a commander flash apparatus as compared with the method of transmitting binary data depending on the presence/absence of flash emission with the timing of a predetermined clock, thereby excelling in a less energy loss.